This Application claims priority to Taiwan Application No. 090107861 entitled xe2x80x9cKey Structure with Scissors-Shaped Frame and a Keyboard Including the Keyxe2x80x9d, filed Apr. 2, 2001.
The present invention generally relates to keyboards.
Keyboards are widely used with various devices, such as computers, to input characters and numerals. To make a key on the keyboard easy to depress, the key is usually designed to function no matter where a force is exerted on the key cap. In other words, even though the force is exerted on the edge of the cap, the force is generally equally distributed over the entire surface of the cap using a scissors-shaped frame for each key. Force distribution is especially important for keyboards used in portable computing devices, which typically require minimal space.
Force distribution is also important in keys of longer width, such as the xe2x80x9cspacexe2x80x9d key and the xe2x80x9cshiftxe2x80x9d key, which typically require additional structure to balance the force exerted on the end of the cap. Generally, a balance bar is disposed under the key cap to balance a force exerted on the end of the cap across the width of the key. By this arrangement, the key may be levelly depressed downwardly even when the force is exerted only on one end of the cap. The balance bar may be disposed on the external side of the scissors-shaped frame such that the balance bar is separated from the frame, as discussed more fully below.
FIGS. 1 and 2 depict the bottom view and side view of a conventional scissors-shaped key structure, respectively. Conventionally, the key structure includes a base 4, a cap 1, a scissors-shaped frame 2, an elastic element (not shown), and a switch element (not shown). Multiple-width keys (such as the space bar) typically further include a balance bar 3. As FIGS. 1 and 2 show, a distance xe2x80x9cdxe2x80x9d between frame 2 and bar 3 is allocated to dispose the balance bar 3. Thus, the projection area of scissors-shaped frame 2 is reduced to accommodate balance bar 3. Particularly, a second end portion 22 of the frame 2a moves back the distance xe2x80x9cdxe2x80x9d to dispose balance bar 3. Additionally, the stroke of the scissors-shaped frame 2 is typically a fixed value. The height of the key 10 is difficult to reduce due to the distance xe2x80x9cdxe2x80x9d and the fixed stroke. Those factors are negative to produce a super-slim key structure.
To solve the problems described above, the present invention discloses a key with scissors-shaped frame, and a keyboard that implements such keys. The key includes a base, a cap, a balance bar, and a scissors-shaped frame. The cap moves vertically relative to the base due to the movement of scissors-shaped frame. The scissors-shaped frame includes a first end portion, a second end portion, a third end portion, and a fourth end portion. The first and second end portions are coupled to the cap, and the third and fourth end portions are coupled to the base. The balance bar may be connected to the second end portion of the scissors-shaped frame, rather than directly to the cap, as appropriate.
In another embodiment, the second end portion is coupled to the cap.
In another embodiment, the second end portion includes a slot to receive the balance bar.